1. Field of the Invention
This invention relates to sealing systems for industrial pumps and specifically relates to a simplified coaxial seal system for rotary fluid pumps.
2. Description of the Related Art
Rotary fluid pumps generally comprise a rotating element, such as an impeller or a rotor, housed within a stationary pump casing. Sealing means are provided between the rotating element and stationary elements of the pump to prevent fluid from infiltrating between the rotating and stationary elements. The type and configuration of sealing means varies widely between types and manufacture of fluid pumps. While it has been known to employ gas as a means of providing a “sealless” sealing systems, most liquid pumps employ mechanical seals.
Sealing assemblies or mechanisms of industrial fluid pumps comprise a sealing element which rotates with the rotating element of the pump and another sealing element which is associated with the stationary elements of the pump, and is, likewise, stationary. Thus, the sealing elements contact each other in a seated arrangement with one sealing element moving relative to the other. As a consequence of the relative movement between the sealing elements, the sealing elements become worn over time and eventually fail. The seal assembly must then be replaced, which usually involves taking the pump off-line, taking the pump apart and replacing the seal assembly or elements of it. Given the complex configuration of known sealing mechanisms or assemblies, the removal and replacement of the seal members is usually very time-consuming and expensive.
In many types of pumps, the seal members are axially aligned adjacent or near each other. Such “in-line” sealing arrangements usually require a significant number of parts, including sealing rings and locking nuts, to produce the desired sealing competency. Additionally, such sealing systems require a significant amount of manpower to assemble and/or to replace the sealing mechanism because the seals and ancillary sealing elements must be properly adjusted and aligned within the pump to assure the integrity of the seal. If the sealing elements are not properly installed, adjusted and aligned, the net pump suction head (NPSH) can be adversely affected, thereby reducing the efficiency of the pump, and the life of the seal can be adversely affected.
Thus, it would be advantageous in the art to provide a seal assembly for a fluid pump which is simply configured, of preferably few parts, and is simple to install, maintain and repair or replace, while providing a competent fluid seal in the pump.